This came after a police sweep that netted 17 suspected Al-Qaeda sympathisers accused of plotting blasts.

"Numerous windows were smashed" at the mosque either late Saturday or early on Sunday and the incident was being investigated, a police official said in an interview.

A second official said he had no information on whether there was a link between the vandalism and the arrests.

Mohammad Alam, the president Islamic Foundation of Toronto, said the incident may be the beginning of religiously motivated reprisals against the country's Muslim population, estimated at more than 600,000.

While he said he backed the government's efforts at stamping out terrorism, Alam noted that nothing has been proven thus far in the case, which has gripped the country.

"Like everybody knows, this is so far all allegation," Alam said. "To us, it doesn't matter what religion they belong to -- if they're a terrorist, they're a terrorist, they should be punished according to the law."